Simplified sensor technology advances to commercialization.

Lateral flow assays--the technology used in pregnancy test kits--are under development to rapidly and reliably identify pathogens in foods. These assays can replace some of the complicated procedures currently used in handling samples in some test kits. The assays detect pathogens after a 24- to 48-hour incubation period. These tests are based on antibodies that determine the presence of many pathogens, including Salmonella and E. coli, in 10 to 15 minutes.

Scientists at Cornell University have focused on the development of rapid, inexpensive, easy-to-use, portable, yet highly sensitive and reliable biosensors that can identify and quantify pathogenic organisms. The ideal device would be a box the size of a large cell phone with a sample inlet hole and a digital readout. One system has been licensed and is moving toward the market place--the lateral flow RNA assay.

The universal nucleic acid lateral flow assay achieves detection limits of 1.5 to 10 fmol (1.5 to 10 nM). The time required for each assay is 10 to 15 minutes, as soon as RNA from the pathogen is available. No special equipment, training or laboratory setting is required to perform the assay. If low numbers of pathogens--as low as five organisms per mL--have to be detected, sample preparation adds about 3 hours to the procedure, which includes RNA purification and amplification using the isothermal nucleic acid sequence-based amplification (NASBA) reaction.

The researchers say that this assay has been able to detect with high specificity five viable C. parvum oocysts, 40 viable E. coli cells, and 10 B. anthracis spores. Device requirements (an added water bath and small centrifuge) are minimal, and total assay times of only 4 hours are possible.

With their system, the scientists have taken advantage of the high specificity of the genome. In addition, instead of using DNA as the analyte, the system detects messenger RNA (mRNA), which is only present when an organism is alive. A dead pathogen will not produce false positive signals. The assay uses liposomes as the signal-generation and signal-amplification system. They can entrap millions of molecules of dye or electrochemical marker and provide a million-fold signal amplification. The liposomes are nanovesicles that serve as the ideal bioanalytical signal-generation reagent, since instantaneous and million-fold amplification can be obtained.

Cornell has licensed the underlying technologies on an exclusive worldwide basis to Innovative Biotechnologies International. This company, in turn, has issued an exclusive sublicense to Cleveland Biosensors of Australia for use in food and water applications. A total of nine issued U.S. patents cover various aspects of the technology. Innovative Biotechnologies expects Cleveland Biosensors to commence commercialization of products based upon the technology within the next six to 12 months.

Further information. Richard A. Montagna, President and CEO, Innovative Biotechnologies International Inc., 335 Lang Blvd., Grand Island, NY 14072; phone: [phone]; fax: [phone]; email: [e-mail].